Centrifugal mill



p 1969 B. N. DUBROVIJN ETAL 3,467,318

CENTRIFUGAL MILL 3 Sheets-Sheet 1 Filed June 2. 1965 &

Sept. 16, 1969 DUBRQVlN ET AL 3,467,318

CENTRIFUGAL MILL Filed June 2, 1965 5 Sheets-Sheet 2 o 0 a e v a 0 l5 0 e p 1969 B. N. DUBROVIN ETAL 3,467,318

CENTRIFUGAL MILL Filed June 2, 1965 3 Sheets-Sheet 3 United States Patent Filed June 2, 1965, Ser. No. 460,699

Int. Cl. B026 19/00,- B07b 7/08 Us. (:1. 241-42 6 Claims ABSTRACT OF THE DISCLOSURE A centrifugal mill for wet grinding having rotatable grinding rollers pivotably mounted by suspension supports from axles secured to a rotor in a housing, the bearings of the grinding rollers being supplied with a lubricant from a reservoir in the casing, the lubricant passing from the bearings externally of the rollers for utilization in the mill for wet grinding.

The present invention relates to centrifugal mills.

The known centrifugal mills incorporate a stationary casing and grinding rollers mounted on a rotor in a drive shaft inside the casing, said rollers being mounted in hearings on said rotor by means of suspension supports.

The disadvantage of the known centrifugal mills is the rapid wear of the rotor and grinding rollers.

An object of the present invention is to prolong the service life of the Working members subject to extensive wear as well as to provide for the possibility of adapting the mill for a wet grinding process.

Other objects of the present invention are to increase the efficiency, improve the technological characteristics, and to bring about a decrease in dimensions and weight of the mill.

According to the present invention, in the accomplishment of said objects the bearings for the grinding rollers are made of elastic material, whereas the rotor, suspension supports and the axles of the grinding rollers are provided with conduits for forced delivery of liquid lubricant to the bearings, thus ensuring continuous lubrication of the latter and avoiding the penetration into the bearings of hard particles of material being crushed.

A circular reservoir communicating with a system of conduits for delivery of lubricant to the bearings of grinding rollers is provided in the rotor cavity.

Given below is a detailed description of the present invention with reference to the accompanying drawings, wherein:

FIG. 1 is a vertical sectional view of the device according to the invention;

FIG. 2 is a cross-sectional view of the device along I-I in FIG. 1;

FIG. 3 is an elevation view partly in section of a system of delivering lubricant to the grinding rollers.

The centrifugal mill of the invention comprises a massive stand 1 with two side plates 2 resting against a foundation. Disposed inside the stand are a pair of bevel gears 3 coupling horizontal driving shaft 4 to vertical main shaft 5 of the machine. The main shaft with bearings 6 is inside central column 7 resting against an mternal part of the stand.

3,467,318 Patented Sept. 16, 1969 ice The walls of the internal and external parts of the stand together with an inclined bottom form a discharge channel 8, through which the crushed product passes to a discharge opening 9. Mounted on the stand is a stationary cylindrical casing 10. The inner working surface of the casing is lined with changeable shells 11 made of wear-resistant materials.

A rotor 12 of the mill is fitted inside the casing on main shaft 5 extending from the column, said rotor carrying grinding rollers 13;

By means of suspension supports 14 and axles 15 the. rollers are fastened to journals 16 of the rotor, said journals being arranged in rows or checker pattern on the outside surface of the rotor drum. The design of the roller units enables the rollers to rotate freely on their axles and to travel in a radial direction, pressing against the internal surface of the mill casing under the action of centrifugal forces and thus grinding the ore.

The grinding rollers and rotor journals are provided with elastic bushings 17 abundantly supplied with water. For the delivery of water, column 18 of the main shaft of the mill is provided with sprinkler 19 through which water passes to circular reservoir 20 of the rotor divided into compartments according to the number of rollers. By means of a system of channels 21 the compartments are connected with the axle bushings of the journals and the rollers, to which bushings liquid is supplied under the action of centrifugal forces.

Fixed to the rotor from above is a distribution disk 22. The product to be crushed is fed onto the disk through the neck of cap 23 of the mill.

The mill casing is provided with a sound-absorbing jacket 24.

The grinding rollers may be made solid .and of a homogeneous material, or they may be protected along their outer surfaces with a coating of wear-resistant materials.

The centrifugal mill proposed hereinabove may also be used for selective grinding of a number of materials, such as dense kimberlite containing adamantine inclusions. For this purpose the rollers should have a coating of elastic material, e.g., rubber of appropriate hardness, such as vulcalone, Capron, etc.

The mill may also be recommended for use in cases when the introduction of metallic iron to the product to be crushed is limited.

We claim:

1. A centrifugal mill for wet grinding comprising a stationary casing, a vertically rotatable drive shaft, a rotor mounted on the drive shaft for rotation therewith, a plurality of axles mounted on said rotor and extending therearound, suspension supports pivotably mounted on respective axles, bearings in said suspension supports, grinding rollers rotatably mounted in said bearings in the suspension supports and a central lubricating system for supplying liquid lubricant to said grinding rollers and externally thereof into a working zone of the mill, said system comprising a liquid reservoir in said rotor and means defining a passageway for said liquid from said reservoir to said axles and then to said bearings via the suspension supports, the passageway being arranged such that liquid flows therethrough from said reservoir under the influence of centrifugal force produced by the rotation of the rotor.

2. A mill as claimed in claim 1 wherein said passageway is constituted by a plurality of interconnected in ternal channels extending from the reservoir to said axles, then from the axles to the suspension supports and then from the suspension supports to the bearings of the grinding rollers.

3. A mill as claimed in claim 1 comprising means dividing the reservoir into a plurality of compartments corresponding to the number of rollers, each compartment being connected to the associated roller via a corresponding passageway.

4. A mill as claimed in claim 3 wherein said lubricating system comprises a stationary vertical conduit for lubricant, and a sprinkler on said conduit facing the reservoir for supplying lubricant thereto.

5. A mill as claimed in claim 3 comprising a journal supporting each axle and secured to said rotor for rotation therewith, each said journal being provided uu'th an internal channel in communication with an associated compartment of said reservoir, said channel constituting a portion of said passageway, the remainder of the passageway extending from said journal through the associated suspension support and then to the bearing of the roller and externally thereof.

4 6. A mill as claimed in claim 1 wherein said bearings are constituted of elastic material.

References Cited UNITED STATES PATENTS 1,175,436 3/1916 Griffin 241-129 XR 1,782,867 11/1930 Davidson 241129 XR 2,219,519 10/ 1940 Fabrin. 2,303,319 12/1942 Beardsley et a1. 241129 XR 2,548,905 4/1951 Odenwellen et a1. 241-110XR FOREIGN PATENTS 82,991 3/ 1935 Sweden.

ROBERT C. RIORDON, Primary Examiner JAMES F. MCKEOWN, Assistant Examiner US. Cl. X.R. 

